Liquid crystal display devices are thin and lightweight, and consume low power. For these properties, liquid crystal display devices are used in various fields. Known display modes for liquid crystal display devices include twisted nematic (TN) mode, super twisted nematic (STN) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, and in-plane switching (IPS) mode.
Although liquid crystal display devices are excellent in various properties, they tend to have problems such as a decrease in luminance and a decrease in contrast owing to a decrease in the voltage holding ratio (VHR). Liquid crystal display devices also tend to cause image sticking (DC image sticking) of display screens owing to residual DC voltage (for example, see Patent Literature 1).
Patent Literature 2, for example, mentions a liquid crystal alignment agent containing a polymer with a polyamic acid and/or an imide structure, an epoxy group-containing compound, and a curing agent for the epoxy group-containing compound, as an approach for enabling formation of a liquid crystal alignment film for suppressing residual DC voltage while a high voltage holding ratio is maintained.
Patent Literature 3, for example, mentions a liquid crystal alignment film on which a silane-based surfactant is chemically adsorbed via a resin film (positive resist), as an approach for enabling formation of a thin, uniform alignment film.